diff --git a/src/EGraphs/egraph.jl b/src/EGraphs/egraph.jl
index 5937ddad..a4f0e5f3 100644
--- a/src/EGraphs/egraph.jl
+++ b/src/EGraphs/egraph.jl
@@ -361,6 +361,7 @@ function Base.union!(
   )
 
   g.classes[id_1] = new_eclass
+  modify!(g, new_eclass)
 
   return true
 end
@@ -425,21 +426,23 @@ function process_unions!(g::EGraph{ExpressionType,AnalysisType})::Int where {Exp
       eclass = g.classes[eclass_id_key]
 
       node_data = make(g, node)
-      if !isnothing(eclass.data)
-        joined_data = join(eclass.data, node_data)
-
-        if joined_data != eclass.data
-          g.classes[eclass_id_key] = EClass{AnalysisType}(eclass_id, eclass.nodes, eclass.parents, joined_data)
-          # eclass.data = joined_data
+      if !isnothing(node_data)
+        if !isnothing(eclass.data)
+          joined_data = join(eclass.data, node_data)
+        
+          if joined_data != eclass.data
+            g.classes[eclass_id_key] = EClass{AnalysisType}(eclass_id, eclass.nodes, eclass.parents, joined_data)
+            # eclass.data = joined_data
+            modify!(g, eclass)
+            append!(g.analysis_pending, eclass.parents)
+          end
+        else
+          g.classes[eclass_id_key] = EClass{AnalysisType}(eclass_id, eclass.nodes, eclass.parents, node_data)
+          # eclass.data = node_data
           modify!(g, eclass)
           append!(g.analysis_pending, eclass.parents)
         end
-      else
-        g.classes[eclass_id_key] = EClass{AnalysisType}(eclass_id, eclass.nodes, eclass.parents, node_data)
-        # eclass.data = node_data
-        modify!(g, eclass)
       end
-
     end
   end
   n_unions
diff --git a/src/EGraphs/saturation.jl b/src/EGraphs/saturation.jl
index 41b2702f..fcc3555f 100644
--- a/src/EGraphs/saturation.jl
+++ b/src/EGraphs/saturation.jl
@@ -86,9 +86,8 @@ function eqsat_search!(
         @debug "$rule is banned"
         continue
       end
-      ids_left = cached_ids(g, rule.left)
-      ids_right = is_bidirectional(rule) ? cached_ids(g, rule.right) : UNDEF_ID_VEC
 
+      ids_left = cached_ids(g, rule.left)
       for i in ids_left
         cansearch(scheduler, rule_idx, i) || continue
         n_matches += rule.ematcher_left!(g, rule_idx, i, rule.stack, ematch_buffer)
@@ -96,6 +95,7 @@ function eqsat_search!(
       end
 
       if is_bidirectional(rule)
+        ids_right = cached_ids(g, rule.right)
         for i in ids_right
           cansearch(scheduler, rule_idx, i) || continue
           n_matches += rule.ematcher_right!(g, rule_idx, i, rule.stack, ematch_buffer)
diff --git a/src/utils.jl b/src/utils.jl
index 2e03b08d..377132e5 100644
--- a/src/utils.jl
+++ b/src/utils.jl
@@ -36,7 +36,7 @@ function buffer_readable(g, limit, ematch_buffer)
   k = length(ematch_buffer)
 
   while k > limit
-    delimiter = ematch_buffer[k]
+    delimiter = ematch_buffer.v[k]
     @assert delimiter == 0xffffffffffffffffffffffffffffffff
     n = k - 1
 
@@ -44,19 +44,19 @@ function buffer_readable(g, limit, ematch_buffer)
     n_elems = 0
     for i in n:-1:1
       n_elems += 1
-      if ematch_buffer[i] == 0xffffffffffffffffffffffffffffffff
+      if ematch_buffer.v[i] == 0xffffffffffffffffffffffffffffffff
         n_elems -= 1
         next_delimiter_idx = i
         break
       end
     end
 
-    match_info = ematch_buffer[next_delimiter_idx + 1]
+    match_info = ematch_buffer.v[next_delimiter_idx + 1]
     id = v_pair_first(match_info)
     rule_idx = reinterpret(Int, v_pair_last(match_info))
     rule_idx = abs(rule_idx)
 
-    bindings = @view ematch_buffer[(next_delimiter_idx + 2):n]
+    bindings = @view ematch_buffer.v[(next_delimiter_idx + 2):n]
 
     print("$id E-Classes: ", map(x -> reinterpret(Int, v_pair_first(x)), bindings))
     print(" Nodes: ", map(x -> reinterpret(Int, v_pair_last(x)), bindings), "\n")
diff --git a/test/egraphs/ematch.jl b/test/egraphs/ematch.jl
index d2c5fb6d..414c7439 100644
--- a/test/egraphs/ematch.jl
+++ b/test/egraphs/ematch.jl
@@ -289,6 +289,22 @@ end
   @test test_equality(some_theory, :(a * b * 0), 0)
 end
 
+@testset "Dynamic rule predicates in EMatcher" begin
+  g = EGraph(:(2 * 3))
+  zero_id = addexpr!(g, 0)
+
+  some_theory = @theory begin
+    ~a * ~b => 0 where (iszero(a) || iszero(b))
+    ~a * ~b --> ~b * ~a
+  end
+
+  Base.iszero(ec::EClass) = in_same_class(g, zero_id, ec.id)
+
+  saturate!(g, some_theory)
+
+  @test test_equality(some_theory, :(a * b * 0), 0)
+end
+
 @testset "Inequalities" begin
   failme = @theory p begin
     p != !p
diff --git a/test/integration/stream_fusion.jl b/test/integration/stream_fusion.jl
index 5b24d3e7..b119c069 100644
--- a/test/integration/stream_fusion.jl
+++ b/test/integration/stream_fusion.jl
@@ -49,7 +49,7 @@ fold_theory = @theory x y z begin
   x::Number * y::Number => x * y
   x::Number + y::Number => x + y
   x::Number / y::Number => x / y
-  x::Number - y::Number => x / y
+  x::Number - y::Number => x - y
   # etc...
 end